The present invention relates to a locking device for locking a movable member such as the backrest or a seat,
In a locking device in JP59-44364U, the front part of the seat is pivotally mounted to the front part of a support base, and the rear part of the seat is urged forward and upward by a spring. In the adjusting metal tool on the lower surface of the rear part of the seat, a plurality of engagement holes communicates with one another via narrower communicating holes to form an adjusting hole. The support base comprises an operating rod which has a larger-diameter portion which passes through the engagement hole, but does not pass through the communicating hole, and a smaller-diameter portion which passes through the smaller-diameter hole to move axially. The smaller-diameter portion fits in the adjusting hole to allow the seat to be adjusted freely in an angle. The smaller-diameter portion is shifted sideward from the adjusting hole to allow the larger-diameter portion to fit in the selected engagement hole, so that the seat is locked at a tilted position determined by the selected engagement hole.
In a conventional chair, an elevating device for the seat or an operating lever for operating a tilting device of the backrest is mounted to the seat, a support base for the backrest, backrest frame or a support member on the lower surface of the seat.
For example, JP2005-163966A discloses the mounting structure in which the end of an operating lever is bent like a crank which actuates a gas spring for urging the backrest to stand up. The shaft of the operating lever is held by a holding tool screwed to the backrest frame.
However, in the locking device in JP59-44364U, an operating rod is loaded by the weight of the occupant who sits on the chair, so that the operating rod is not moved. To move the operating rod, it is necessary for the occupant to leave the seat or to stand up thereby causing poor operativity.
In JP2005-163966A, in order to mount the operating lever, it is necessary to fix the holding metal tool to the support member, which is complicated and needs time. The number of parts is increased.